1. Technical Field
The present invention relates generally to a tube trimming technique and specifically to a process and apparatus that forms trim lines on the end of a rectangular tube for frame assembly purposes.
2. Discussion
In motor vehicle frame construction applications, it is well known to shape the ends of frame cross members so that the cross member ends can be fitted to frame side rail members with a high degree of accuracy. Once the frame cross members are mated with the frame side rail members, the cross members are secured to the side rail members via well known techniques, such as welding or brazing.
Techniques for forming trim lines on tubular cross member ends are well known in the art. Typically, these techniques form the trim lines by a laser trimming or plasma arcing process. Significant disadvantages of the traditional processes include the high associated cost of lasers and other equipment required to implement the processes and the slow cycle time required to achieve the desired trim lines.
Examples of traditional techniques for making strategic cuts in tubing are disclosed in U.S. Pat. No. 4,974,436 entitled "Cutting Tool to Facilitate Bending of Hollow Tubing" which issued to Nakatsuji on Dec. 4, 1990; and U.S. Pat. No. 4,930,384 entitled "Die for Notching Hollow Tubing" which issued to Nakatsuji on Jun. 5, 1990. An example of a traditional process of mitering tube ends is disclosed in U.S. Pat. No. 3,074,302 entitled "Method of Preparing Mitered Tubular Joints" which issued to Coulon et al. on Jan. 22, 1963. However, these techniques suffer one or more problems which do not lend themselves to high volume production of the products contemplated by the present invention.